Elastomeric articles are widely employed in the closure art and particularly for elastomeric packaging components. Such articles are especially useful for sealing vials or other containers, usually of glass, for use in packaging medicaments, and for plungers in hypodermic syringes, and the like. Such articles are commonly composed of rubber which is, of course, normally compounded with vulcanization accelerators, vulcanizing agents, sulfur, carbon black, zinc oxide, titanium dioxide, and other pigments, and a wide diversity of other ingredients which are inimical to medicaments. Such foreign materials inevitably leach out or otherwise contaminate the medicaments, or even react with them to produce unwanted or even toxic materials. It has been customary, therefore, to take measures to prevent contact between the rubber and the medicament. This has previously been done by interposing a barrier of an inert plastic such as polypropylene, polytetrafluorethylene or the like. Such a physical barrier layer has been composed of an inert plastic in the form of a separate element of the closure, or has been formed by laminating a film of an inert plastic over the rubber stopper, or other packaging component.
Another problem common to such packaging, particularly for use in the medical field, has been that the rubber stoppers or other packaging components have a high coefficient of friction which makes it difficult to eliminate foreign matter on the surface of the articles. Moreover, some sort of lubricant or closure coating is needed to reduce the coefficient of friction of the components to enhance the physical characteristics of the closures to facilitate handling and sealing of the containers by automatic filling and sealing equipment. Closure coatings to overcome these problems have typically been based upon silicone resins. Such coatings, while still widely employed, are now considered undesirable since they tend to migrate into the packaged solution, for example, in the form of globules and it is not known what the long term effects are of silicones in the body. Indeed, the use of silicones for these purposes may be banned in a few years.
Therefore, there has been a clear need in the art for a coating for rubber closures which minimizes or totally eliminates the need for silicone lubricants in the assembly, closure and sealing of elastomeric packaging components, and which is also capable of preventing contamination of packaged medicaments by foreign matter on the surface of the packaging components, such as stoppers or the like.